Joist



Nov. 2, 193 7.

E. D. CODDINGTON 2,097,722

JoisT Filed Sept. 5, 1935 f! W b 14 3/ L 1' 2 z I l/ l l/ [B was MM Patented Nov. 2, 1937 PATENT orr er.

2,097,722 JOIST Edwin D.

to Reynolds Coddington, Milwaukee,

Corporation, New

Wis, assignor York, N. Y., a

corporation of Delaware Application September 3,

2 Claims.

The present invention relates to a skeletonized metal joist having a cementitious fill suitable for receiving nails.

The objects of the invention include, among others, the provision of the following:

A joist comprising opposed chord members for the reception of nails and a simple and efficient web therebetween;

Improved reenforcing for a skeletonized joist;

An arrangement of channel members producing an exceptionally strong joist; and

A combination of channel members of different characteristics for the production of a joist of great strength in comparison with its weight.

These objects, and such other objects as may appear hereinafter, are obtained by the novel construction, unique combination, and improved arrangement of the several elements which constitute the invention, a single embodiment of which is illustrated in the accompanying sheet of drawings, hereby made a part of this application, and in which:

Figure 1 is a side elevation of a joist embodying one form of the invention;

Figure 2 is a longitudinal section on the line 2-2 of Figure 1;

Figure 3 is a transverse section on the line 3-4 of Figure l; and

Figure 4 is a transverse section on the line 4-4 of Figure 1.

Like reference characters are used to designate similar parts in the drawing and in the description of the invention which follows:

The illustrated embodiment of the invention comprises opposed nail receiving chords and an intermediate web. End members of any suitable construction and adapted to receive nails may be supplied at the ends of and between the top and bottom chords of the joist.

The structure of the top and bottom chords of the joist is the same, the position of the two chords being reversed. The top chord, designated A, as shown in the drawing, comprises a channel it, opposed sides H and i2 flaring outwardly, a horizontal flange l3 on side H, and a similar flange M on side 12.

The channel member is closed to make a tube by a strip of material l5 which may be of the same width as the channel member and its flanges, or of slightly less widt Spot welding ii and i8 unites the flanges l3 and I4, respectively, to the top l5. The channel It is closed by the strip metal member l5 and perforations it are provided through the latter in a plurality of rows coextensive with the length of this mem- 1935, Serial N... 39,027

ber. Enclosed within the channel-shaped base member I0 is a nailable core l9 composed of a mixture of gypsum, Portland cement and sawdust represented approximately in the proportions, by weight, 55:20:9. This mixture may be packed into the dry state and moisture then introduced through the perforations It to supply the necessary water of crystallization to the mixture, which thereupon hardens. This process of fabrication is more particularly described in my copending application Serial No. 39,022, filed September 3, 1935.

The bottom chord B comprises a base Zll having sides 2| and 22, the sides 2| and 22 having horizontal flanges 23 and 24. There is a sheet metal strip 25 secured to the flanges 23 and Z lby spot welding 26 and 21. A cementitious flll 28 provides a suitable nail receiving body enclosed by the channel 29 and the metal strip. The cover strip 25 may similarly be provided with perfor-ations 29 throughout its length corresponding to the perforations it of the top strip H5.

The two chords are spaced apart by a web composed of individual channel members, the end members 20 of which are perpendicular to the base members and the intermediate members of which are alternately oppositely diagonal in respect thereto. The intermediate members are designated 3|. Each channel section comprises a central flat portion 34 and sides or flanges 35 and 3E. The ends of each of members 3! are secured to the base members l0 and 26 by arc welding or by any other suitable means. The arrangement of the intermediate members is as follows:

Each end member 30 is spaced a predetermined distance from the end of the base members and is secured in position by spot welding. The end member 30 is so positioned that a nail-receiving part may be secured between the two base members l0 and 28 in alinement with the ends thereof. Partly overlapping one end of a channel member 30 is a diagonally disposed member at and partly overlapping the opposite end of the member 3! is a second diagonal member. The members 3%] and 3l have their backs 34 in abutment at the overlapping sections. A plurality of diagonal members 3| partially overlapping extend to the opposite end of the joist where the last diagonal member partly overlaps a second end member 3%. All of the members 39 and Si are secured in position, as previously indicated, by spot welding or by other suitable means.

The structure illustrated and described is extremely simple.

The chords receiving the cementitious fill are economical to manufacture d the strips I5 and 25 are also inexpensive, easily attached and readily penetrable by suitable nails.

The alternate arrangement of the channel sections 3| gives strength to overcome all normal tion under compression stresses.

I claim:

1. A composite joist comprising a pair of tubular chords each chords in spaced relation, said Web comprising a series of diagonally disposed channel Sections, alternate channel sections being reversely inclined and the ends only of contiguous channel sections being overlapped and united back to back and fiat faces of the chords.

2. A composite joist comprising a pair of reversely disposed tubular chords each constituting terminal edges to the flat faces of the trapezoidal-shaped casings.

EDWIN D. CODDINGTON. 

